The IVth World Congress on Pain, sponsored by the International Association for the Study of Pain (IASP) will be held in Seattle, Washington on Aug. 31-Sept. 5, 1984. The goals and objectives of this Congress are to bring together scientists, physicians, dentists, psychologists, nurses, and other health professionals from various parts of the world, representing virtually every basic science and clinical discipline, to report new information and to reappraise current knowledge on pain mechanisms and various therapeutic modalities in current use. The scientific program of the Congress includes plenary (single track) sessions, breakfast and lunch sessions, workshops, and free communications. The plenary session on: Spinal Mechanisms of Analgesia and Their Clinical Application, and the special plenary lectures on: The Primary Afferent Nociceptor, Peptides as Pain Transmitters, Mechanisms of Hyperalgesia, Mechanisms of Painful Neuropathies, Thalamocortical Mechanisms in Pain Transmission, and Trigeminal Pain, as well as four breakfast sessions, ten workshops, and a significant percentage of the free communications will deal directly with the area of research on functions of the nervous system of primary interest to NINCDS. Based on our experiences of the previous IASP world congresses, it is anticipated that: (1) over 2000 biomedical scientists and health professionals, representing every basic science and clnical discipline from over 40 countries will attend the IVth World Congress on Pain; (2) about 550 presentations will be made; (3) the Congress will enhance interaction, communication, and cross-fertilization among the participants of different disciplines; and (4) it will greatly facilitate the rapid application of new knowledge to the diagnosis and treatment of acute and chronic pain. Moreover, the Congress should help define more clearly the needs and directions of future research efforts and provide opportunities for collaborative interdisciplinary study and treatment of acute and chronic pain. The ultimate goal is to help improve the care of patients with acute and chronic pain, which currently constitutes a major national and world health and economic problem.